Traditionally, investigations of the determinants of children's word learning have focused on the importance of either child variables (e.g., word learning strategies) or word variables (e.g., complexity of a word's meaning). However, adult word use in speech to children also may have important effects. This position is supported by reports that the frequencies with which adults use spatial, temporal, and similarity words in child-directed speech are highly correlated with the order of acquisition of the words. Studies by this investigator indicate that adults may use several speech strategies when speaking to young children about concrete objects. The "basic level orienting" strategy involves emphasizing basic level words (i.e., words of intermediate generality like "dog") even when using words at other taxonomic levels (e.g., "collie" or "animal"). The "ty picality orienting strategy" involves avoiding use of a category label for category members that are considered atypical exemplars. Do these adult strategies have any significant effects on children's knowledge of concrete vocabulary? The proposed study will address this question by investigating whether mothers' tendencies to use such strategies are related to their children's knowledge of concrete words. Subjects will be mothers (who are primary caretakers) and their young children. Mothers' use of concrete vocabulary to their children will be assessed using procedures adapted from previous studies. The overall design of the study is quasi-experimental. Children of mothers who score low on a tendency to use a particular speech strategy will be compared to children of mothers who score high on that strategic tendencey. Children will be compared on several measures of their knowledge of concrete vocabulary and on their ability to understand relationships among words. The relationship between mothers' speech strategies and younger (18-month-0ld) versus older (36-month-old) children's performance on vocabulary measures wll be analyzed. This research should help to establish whether relationships exist between mothers; speech strategies and their children's knowledge of concrete vocabulary. Future studies will be aimed at determining whether this relationship is causal, i.e., whether adult speech strategies directly affect children's word learning.